Transmitting and receiving control protocol data unit having processing time information

ABSTRACT

The present invention relates to transmitting and receiving control protocol data. A transmitter transmits a control protocol unit having processing time information, wherein the processing time information indicates to a receiver of when to process the control protocol data unit. Accordingly, the receiver processes the control protocol data unit according to the processing time information.

CROSS-REFERENCE TO RELATED APPLICATIONS

Pursuant to 35 U.S.C. § 119(a), this application claims the benefit ofearlier filing date and right of priority to Korean Application No.2004-0043754, filed on Jun. 14, 2004, the contents of which is herebyincorporated by reference herein in its entirety.

FIELD OF THE INVENTION

The present invention relates to transmitting and receiving controlprotocol data, and more particularly, to transmitting and receiving acontrol protocol data unit having processing time information, whereinthe processing time information informs a receiver of when to processthe control protocol data unit.

BACKGROUND OF THE INVENTION

A universal mobile telecommunications system (UMTS) is athird-generation mobile communications system evolving from a globalsystem for mobile communications system (GSM), which is the Europeanstandard. The UMTS is aimed at providing enhanced mobile communicationsservices based on the GSM core network and wideband code-divisionmultiple-access (W-CDMA) technologies.

In December 1998, ETSI of Europe, ARIB/TTC of Japan, T1 of the UnitedStates, and TTA of Korea formed a Third Generation Partnership Project(3GPP) for creating detailed specifications of the UMTS technology.Within the 3GPP, in order to achieve rapid and efficient technicaldevelopment of the UMTS, five technical specification groups (TSG) havebeen created for determining the specification of the UMTS byconsidering the independent nature of the network elements and theiroperations.

Each TSG develops, approves, and manages the specification within arelated region. Among these groups, the radio access network (RAN) group(TSG-RAN) develops the specifications for the functions, requirements,and interface of the UMTS terrestrial radio access network (UTRAN),which is a new radio access network for supporting W-CDMA accesstechnology in the UMTS.

A related art UMTS network structure 1 is illustrated in FIG. 1. Asshown, a mobile terminal, or user equipment (UE) 2 is connected to acore network (CN) 4 through a UMTS terrestrial radio access network(UTRAN) 6. The UTRAN 6 configures, maintains and manages a radio accessbearer for communications between the UE 2 and the core network 4 tomeet end-to-end quality of service requirements.

The UTRAN 6 includes a plurality of radio network subsystems (RNS) 8,each of which comprises one radio network controller (RNC) 10 for aplurality base stations, or Node Bs 12. The RNC 10 connected to a givenbase station 12 is the controlling RNC for allocating and managing thecommon resources provided for any number of UEs 2 operating in one cell.One or more cells exist in one Node B. The controlling RNC 10 controlstraffic load, cell congestion, and the acceptance of new radio links.Each Node B 12 may receive an uplink signal from a UE 2 and may transmita downlink signals to the UE 2. Each Node B 12 serves as an access pointenabling a UE 2 to connect to the UTRAN 6, while an RNC 10 serves as anaccess point for connecting the corresponding Node Bs to the corenetwork 4.

Among the radio network subsystems 8 of the UTRAN 6, the serving RNC 10is the RNC managing dedicated radio resources for the provision ofservices to a specific UE 2 and is the access point to the core network4 for data transfer to the specific UE. All other RNCs 10 connected tothe UE 2 are drift RNCs, such that there is only one serving RNCconnecting the UE to the core network 4 via the UTRAN 6. The drift RNCs10 facilitate the routing of user data and allocate codes as commonresources.

The interface between the UE 2 and the UTRAN 6 is realized through aradio interface protocol established in accordance with radio accessnetwork specifications describing a physical layer (L1), a data linklayer (L2) and a network layer (L3) described in, for example, 3GPPspecifications. These layers are based on the lower three layers of anopen system interconnection (OSI) model that is well known incommunications systems.

A related art architecture of the radio interface protocol isillustrated in FIG. 2. As shown, the radio interface protocol is dividedhorizontally into a physical layer, a data link layer, and a networklayer, and is divided vertically into a user plane for carrying datatraffic such as voice signals and Internet protocol packet transmissionsand a control plane for carrying control information for the maintenanceand management of the interface.

The physical layer (PHY) provides information transfer service to ahigher layer and is linked via transport channels to a medium accesscontrol (MAC) layer. Data travels between the MAC layer and the physicallayer via a transport channel. The transport channel is divided into adedicated transport channel and a common transport channel depending onwhether a channel is shared. Also, data transmission is performedthrough a physical channel between different physical layers, namely,between physical layers of a sending side (transmitter) and a receivingside (receiver).

The second layer includes a MAC layer, a radio link control (RLC) layer,a broadcast/multicast control (BMC) layer and a packet data convergenceprotocol (PDCP) layer. The MAC layer maps various logical channels tovarious transport channels. The MAC layer also multiplexes logicalchannels by mapping several logical channels to one transport channel.The MAC layer is connected to an upper RLC layer via the logicalchannel. The logical channel can be divided into a control channel fortransmitting control plane information a traffic channel fortransmitting user plane information according to the type of informationtransmitted.

The MAC layer is divided into a MAC-b sublayer, a MAC-d sublayer, aMAC-c/sh sublayer, a MAC-hs sublayer and a MAC-e sublayer according tothe type of transport channel being managed. The MAC-b sublayer managesa broadcast channel (BCH), which is a transport channel handling thebroadcast of system information. The MAC-c/sh sublayer manages commontransport channels such as an FACH (Forward Access Channel) or a DSCH(Downlink Shared Channel) that is shared by other terminals. The MAC-dsublayer handles the managing of a DCH (Dedicated Channel), namely, adedicated transport channel for a specific terminal. In order to supportuplink and downlink high speed data transmissions, the MAC-hs sublayermanages an HS-DSCH (High Speed Downlink Shared Channel), namely, atransport channel for high speed downlink data transmission, and theMAC-e sublayer manages an E-DCH (Enhanced Dedicated Channel), namely, atransport channel for high speed uplink data transmissions.

The RLC layer guarantees a quality of service (QoS) of each radio bearer(RB) and handles the transmission of corresponding data. The RLC layerincludes one or two independent RLC entities for each RB in order toguarantee a particular QoS of each RB. The RLC layer also provides threeRLC modes, namely, a Transparent Mode (TM, an Unacknowledged Mode (UM)and an Acknowledged Mode (AM), to support various types of QoS. Also,the RLC controls the size of data to be suitable for a lower layer intransmitting over a radio interface. For this purpose, the RLC segmentsand concatenates the data received from the upper layer.

A PDCP (Packet Data Convergence Protocol) layer is a higher layer of theRLC layer and allows the data transmitted through a network protocol(such as an IPv4 or IPv6) to be effectively transmitted over a radiointerface with a relatively small bandwidth. To achieve this, the PDCPlayer performs a header compression function wherein only necessaryinformation is transmitted in a header part of the data to therebyincrease transmission efficiency over the radio interface. Because thePDCP layer performs the header compression as a basic function, itexists only at a packet switched (PS) domain. One PDCP entity isprovided per RB to provide an effective header compression function withrespect to each PS service.

A BMC (Broadcast/Multicast Control) layer, located at an upper portionof the RLC layer in the second layer (L2), schedules a cell broadcastmessage and broadcasts the message to terminals located in a specificcell.

A radio resource control (RRC) layer located at the lowest portion ofthe third layer (L3) is defined in the control plane and controls theparameters of the first and second layers with respect to theestablishment, reconfiguration and release of RBs. The RRC layer alsocontrols logical channels, transport channels and physical channels.Here, the RB refers to a logical path provided by the first and secondlayers of the radio protocol for data transmission between the terminaland the UTRAN. In general, the establishment of the RB refers tostipulating the characteristics of a protocol layer and a channelrequired for providing a specific data service, and setting theirrespective detailed parameters and operation methods.

The details of the RLC layer will be now be explained. The RLC layerguarantees a QoS of each RB and transmits data according to the QoS.Because the second layer of the radio protocol provides the RB serviceto an upper layer, the entire second layer influences the QoS;particularly, the RLC influences the QoS. The RLC establishes anindependent RLC entity for every RB in order to assure an intrinsic(unique) QoS of the RB. Various types of QoS are supported by using theTM, the UM and the AM modes. The three RLC modes support different QoSfrom one another, and different operation methods are used for eachmode. The detailed functions thereof are also different.

Each RLC operation mode (TM, UM and AM) will be now explained. First,the TM RLC is a mode in which an RLC SDU transferred from an upper layerdoes not have any overhead for constructing an RLC PDU. That is, the RLCpasses the SDU transparently and hence is named “transparent” mode RLC.The TM RLC with this characteristic performs the following functions inthe user plane and the control plane.

In the user plane, because of a short data handling time in the RLC, theTM RLC manages a transmission of real-time circuit data such as voice orstreaming data of a circuit service domain (CS domain). While in thecontrol plane, there is no overhead in the RLC such that the TM RLCmanages a transmission of an RRC message from a non-specific UE on theuplink and a transmission of an RRC message broadcast to all UEs withina cell on the downlink.

Unlike the TM mode, a mode in which an overhead is added at the RLC isreferred to as a non-transparent mode. The non-transparent mode includesan unacknowledged mode (UM), which does not receive an acknowledgedresponse for transmitted data, and an acknowledged mode (AM), which doesreceive an acknowledged response. The UM RLC sends PDUs, each of whichhaving a PDU header containing a sequence number (SN) added thereto, soas to allow a receiver to know which PDU has been lost during datatransmission. By this function, the UM RLC manages in the user plane, atransmission of broadcast/multicast data or real-time packet data suchas voice (e.g., VoIP) or streaming data of a PS domain. Simultaneously,the UM RLC manages in the control plane, a transmission of an RRCmessage, which does not require a reception acknowledged response, amongRRC messages transmitted to a specific UE or a specific UE group withina cell.

The AM RLC, similar to the UM RLC, constructs a PDU by adding a PDUheader containing the SN and sends the PDU to a receiver. However,unlike the UM RLC, the receiver sends an acknowledgment for the PDUtransmitted from a transmitter in the AM RLC. By sending theacknowledgment, the receiver can request the transmitter to retransmit aPDU that was unsuccessfully received. This is the most essentialcharacteristic of the AM RLC.

As a result, the AM RLC aims to guarantee an error-free datatransmission by performing retransmissions. Accordingly, the AM RLCmanages the transmission of non-real time packet data such as a TCP/IP(Transmission Control Protocol/Internet Protocol) of the PS domain inthe user plane. In the control plane, the AM RLC manages a transmissionof an RRC message requiring a reception acknowledged response among theRRC messages transmitted to a specific UE within a cell.

Furthermore, regarding the directional properties, the TM RLC and the UMRLC are used for uni-directional communication, while the AM RLC is usedfor bi-directional communication because of the feedback from thereceiver. Bi-directional communication is usually used in apoint-to-point communication scheme. Thus, the AM RLC uses only adedicated logical channel. In addition, in the schematic aspect of thethree operational modes, transmission or reception is achieved by oneRLC entity in the TM RLC and the UM RLC. However, in the AM RLC, boththe transmitter and the receiver each have one RLC entity.

The AM RLC has a complicated scheme because of its retransmissionfunction. The AM RLC includes a retransmission buffer in addition to atransmission/reception buffer for managing retransmissions. Inparticular, the AM RLC performs various functions such as using atransmitter/receiver window for flow control, using a polling procedureby which a transmitter requests status information from a receiver of apeer RLC entity, reporting status information by which the receiverreports its own buffer state to the transmitter of the peer RLC entity,using a status PDU carrying the status information, using a piggybackprocedure to insert the status PDU into a data PDU for increasing theefficiency of data transmissions, as well as other functions.

In the AM RLC, when a serious error is found during an operation of theAM RLC entity, a reset PDU for requesting the AM RLC entity of acounterpart to reset some or all operations and parameters, a reset ACKPDU for providing a response with respect to the reset PDU, or the like,are used. For supporting these functions, the AM RLC must have variousprotocol parameters, status variables and a timer.

A PDU used for controlling a data transmission in the AM RLC, such asthe status information report or the status PDU and the reset PDU, isreferred to as a control PDU. A PDU used for transferring user data isreferred to as a data PDU. Hence, the PDUs used in the AM RLC aregenerally divided into data PDUs and control PDUs. The control PDUs arefurther classified into four different PDUs, namely, a status PDU, apiggybacked status PDU, a reset PDU and a reset ACK PDU.

In general, a reset procedure corresponds to a situation requiring theuse of the control PDU. The reset procedure is used for solvingerroneous situations at an operation of the AM RLC, such as situationswhere different sequence numbers are used, or where a PDU (or SDU) hasbeen unsuccessfully transmitted more than a certain number of times.When using the reset procedure, the AM RLCs of the receiver and thetransmitter initialize their environment variables to enter into a statethat again allows communication.

First, a party that decides to initiate the reset procedure, namely, theAM RLC of the transmitter, transmits to the receiver a reset PDUcontaining an HFN (Hyper Frame Number) value of its transmittingdirection that is currently being used. When the reset PDU is delivered,the AM RLC of the receiver resets the HFN value of its receivingdirection and initializes the environment variables such as a sequencenumber. Also, the AM RLC of the receiver transmits a reset ACK PDUcontaining the HFN of its transmitting direction to the AM RLC of thetransmitter. When the reset ACK PDU is received, the AM RLC of thetransmitter resets the HFN value of its receiving direction and theninitializes the environment variables.

Hereinafter, the format of an RLC PDU used in an AM RLC entity will bedescribed. FIG. 3 illustrates a format of an AM RLC PDU, a data PDU usedwhen transmitting data. Referring to FIG. 3, the AM RLC PDU is used whenthe AM RLC entity desires to transmit user data or piggybacked statusinformation and a polling bit. A portion of the user data comprises 8bits or integer multiples thereof. A header of the AM RLC PDU comprisesa sequence number having a size of two octets. Also, a portion of theheader of the AM RLC PDU includes a length indicator.

FIG. 4 illustrates a format of a status PDU (STATUS PDU). The status PDUcomprises plurality of SUFIs (Super Fields), each of which can bedifferent from one another. A size of the status PDU is variable orrestricted to be the same size as the size of the greatest RLC PDU of alogical channel by which the status PDU is transmitted. Here, the SUFIsperform the function of reporting information about which AM RLC PDU hasbeen successfully or unsuccessfully received at the receiving end, ormay contain indications necessary for varying a size or a position of areceiver window. Each SUFI is formed of three parts of parametersincluding a type, a length and a value.

FIG. 5 illustrates a format of a piggybacked status PDU. The piggybackedstatus PDU has a similar format to that of the status PDU, but it isdifferent therefrom in that a D/C field is substituted for a reservedbit (R2). This piggybacked status PDU is inserted into the AM RLC PDUwhen the AM RLC PDU has sufficient space remaining therein. Here, thePDU type value is always defined as 000.

FIG. 6 illustrates a format of a reset PDU/reset ACK PDU. The reset PDUcontains a sequence number called an “RSN” having a size of one bit. Thereset ACK PDU is transmitted as a response for a received reset PDU,whereby the reset ACK PDU is transmitted together with the RSN that iscontained in the received reset PDU.

In this case, the parameters used in the PDU format may be indicated asfollows.

D/C field: This value informs whether a corresponding PDU is a controlPDU or a data PDU.

PDU type: This value informs of a type of the control PDU. Specifically,this value informs whether the corresponding PDU is a reset PDU or astatus PDU.

Sequence number: This value refers to sequence number information of theAM RLC PDU.

Polling bit: This value is set when requesting a status report to areceiver.

Extension bit (E): This value refers to whether or not the followingoctet is a length indicator.

Reserved bit (R1): This value is used for a reset PDU or a reset ACK PDUand coded as 000.

Header extension bit (HE): This value refers to whether the followingoctet is a length indicator or data.

Length indicator: This value informs of a position of a boundary betweendifferent SDUs, if such exists within a data portion of a PDU.

PAD: This portion refers to a padding region that is not used in the AMRLC PDU.

Hereafter, HSDPA (High Speed Downlink Packet Access) technology will beexplained. As wireless Internet access technology becomes more popularand subscribers therefore continue to increase, various services relatedthereto are being provided. Thus, techniques and systems allowing highertransmission rates are needed for supporting these services. In 3GPP,research for enhancing UMTS network technologies and providing highertransmission rates are being conducted. Particularly, the HSDPA (HighSpeed Downlink Packet Access) system is getting much attention.

Various new techniques have been introduced for supporting the HSDPA.One of these techniques is the HARQ (Hybrid Automatic Repeat Request)technique. The HARQ technique is a retransmission method, which isdifferent from the retransmission method for packets performed by theRLC layer. The HARQ method is used in connection with a physical layerand combines retransmitted data with a previously received data so as toguarantee a higher restoring (decoding) ratio. Specifically, in the HARQtechnique, an unsuccessfully transmitted packet is not discarded butstored, and then combined with a retransmitted packet prior to a codingstep so as to restore (decode) that packet.

In order to support the HARQ function more effectively, a HARQ blockexists in the MAC-hs sublayer of a Node B. The HARQ block includes HARQentities for managing the HARQ operation of a UE to be supported. Also,one HARQ entity exists with respect to each UE. Furthermore, each HARQentity has various HARQ processes therein, each process being used forhandling the control of the HARQ operations and used for transmittingspecific data. Each HARQ process may share and use a plurality of dataunits, but only one is processed for one TTI (Transmission TimeInterval). Therefore, when data transmission is successful, the HARQprocess becomes empty and thus may be used for transmitting other data.However, when data transmission is unsuccessful, the HARQ processcontinues to store the corresponding data until it is successfullytransmitted or discarded.

Considering the data transmission in the MAC-hs of the Node B in moredetail, the Node B reconstructs (decodes) data units received from theRNC to generate MAC-hs PDUs. The corresponding PDUs are then allocatedto each HARQ process. In this case, the MAC-hs PDUs transmitted fromeach HARQ process may be successfully sent to a UE all at once; however,this may not always be the case.

For instance, assume that a previously generated MAC-hs PDU#1 isallocated to a HARQ process A and a subsequently generated MAC-hs PDU#2is allocated to a HARQ process B. In general, each HARQ process does notperform transmission simultaneously, but respectively operatesindependently. Therefore, when the HARQ process A is continuouslyunsuccessful in transmitting the MAC-hs PDU#1 and the HARQ process Bsuccessfully transmits the MAC-hs PDU#2 earlier than the HARQ process A,it may occur that the MAC-hs PDU#2 containing the subsequently generateddata (namely, the data that arrives at the Node B later) may be receivedand processed by the UE earlier than the previously generated MAC-hsPDU#1 and then processed. That is, according to the HARQ process, theMAC-hs PDUs may not always be delivered to the UE in the order in whichthey were generated at the Node B. As a result, the RLC PDUs containedin the MAC-hs PDU may also not necessarily be delivered to the RLC insequential order.

The related art has been designed to allow PDUs to arrive at the AM RLCof a receiver in the order that they were transmitted by the AM RLC of atransmitter. That is, in the related art, when the AM RLC of thereceiver received a control PDU, that received control PDU wasdetermined to have been transmitted subsequent to a last received RLCPDU, and the received control PDU was immediately processed.

However, as aforementioned, a technique such as HSDPA transmits PDUs byusing various HARQ processes at once, such that the PDUs are notdelivered to the AM RLC of the receiver in the order that they weretransmitted from the AM RLC of the transmitter. This situation isreferred to as an ‘out of sequence delivery’. In other words, PDUs whichshould be delivered later may arrive at the receiver earlier than theformer generated PDUs. In spite of this, if the AM RLC of the receiverimmediately processes a corresponding control PDU as soon as it isdelivered, like in the related art, proper communication may notcontinue, thus leading to serious problems.

For instance, assume that an AM RLC performs a reset procedure. In thereset procedure, the AM RLC of the transmitter first transmits to thereceiver a reset PDU, which is a type of control PDU containing the HFNvalue currently being used for its transmitting direction. Then, uponreceiving delivery of the reset PDU, the AM RLC of the receiver resetsthe HFN value of its receiving direction and also initializes a sequencenumber thereof.

However, for the AM RLC PDUs transmitted prior to the reset PDU, the HFNvalues before performing a reset procedure are used. Moreover, thesequence numbers before initialization are used. If the AM RLC PDUs,which have been generated and transmitted prior to the reset PDUs,arrive at the receiver subsequent to the reset PDUs, then thesubsequent-arriving AM RLC PDUs would be interpreted to have arrivedafter the environment variables of the receiver had already beenupgraded to new values by the reset PDU. Therefore, the AM RLC of thereceiver can not properly restore (decode) the AM RLC PDUs that usedprevious environment variables before any updating. Furthermore, the AMRLC of the receiver undesirably continues to update the environmentvariables while being in an erroneous state, and also continues torestore (decode) AM RLC PDUs to be subsequently transmitted thereto byusing the erroneous environment variables. As a result, propercommunication can no longer be continued.

SUMMARY OF THE INVENTION

The present invention is directed to transmitting and receiving acontrol protocol data unit having processing time information, whereinthe processing time information informs a receiver of when to processthe control protocol data unit.

Additional features and advantages of the invention will be set forth inthe description which follows, and in part will be apparent from thedescription, or may be learned by practice of the invention. Theobjectives and other advantages of the invention will be realized andattained by the structure particularly pointed out in the writtendescription and claims hereof as well as the appended drawings.

To achieve these and other advantages and in accordance with the purposeof the present invention, as embodied and broadly described, the presentinvention is embodied in a receiver for receiving a control protocoldata unit in a receiving side of a wireless communication system, thereceiver comprising means for receiving the control protocol data unithaving processing time information associated with the control data unitin a radio link control module and means for processing the controlprotocol data unit according to the processing time information, whereinthe processing time information indicates when to process the controlprotocol data unit by the receiving side.

Preferably, the processing time information comprises a sequence numberassociated with a data unit transmitted sequentially with the controlprotocol data unit from a transmitting side to the receiving side. Thedata unit and the control protocol data unit are used for at least oneof downlink communication and uplink communication. The radio linkcontrol module processes the control protocol data unit after processinga data unit having the same sequence number included in the processingtime information of the control protocol data unit. Alternatively, theradio link control module processes the control protocol data unit afterprocessing a data unit having a sequence number that is one smaller thanthe sequence number included in the processing time information of thecontrol protocol data unit.

In one aspect of the present invention, the processing time informationcomprises a sequence number of a data unit transmitted before thecontrol protocol data unit is transmitted from a transmitting side. Theprocessing time information may also comprise a sequence number that issubsequent to a sequence number of a data unit transmitted before thecontrol protocol data unit is transmitted from a transmitting side.Additionally, the processing time information may comprise a sequencenumber of a data unit transmitted after the control protocol data unitis transmitted from a transmitting side.

Preferably, the processing time information is positioned in any of afirst, a last, or a middle part of the control protocol data unit. Theprocessing time information may be positioned in a super field of thecontrol protocol data unit.

In another aspect of the present invention, the radio link controlmodule is operated in an acknowledged mode. Also, the control protocoldata unit is at least one of a status protocol data unit, a piggybackedstatus protocol data unit, a reset protocol data unit, and a resetacknowledgment protocol data unit.

In a further aspect of the invention, the receiver further comprisesmeans for receiving an instruction from an upper layer indicating to theradio link control module whether to process the control protocol dataunit immediately or according to the processing time information.

In another embodiment of the present invention, a transmitter fortransmitting a control protocol data unit from a transmitting side of awireless communication system comprises means for generating a data unitin a radio link control module using data blocks received from an upperlayer, means for generating the control protocol data unit havingprocessing time information associated with the control protocol dataunit in the radio link control module, wherein the processing timeinformation indicates to a radio link control module of a receiving sidewhen to process the control protocol data unit, and means fortransmitting the control protocol data unit and the data unit to thereceiving side in at least one of a downlink direction and an uplinkdirection.

Preferably, the processing time information comprises a sequence numberassociated with a data unit transmitted sequentially with the controlprotocol data unit from a transmitting side to the receiving side.

In one aspect of the present invention, the processing time informationcomprises a sequence number of a data unit transmitted before thecontrol protocol data unit is transmitted from a transmitting side. Theprocessing time information may also comprise a sequence number that issubsequent to a sequence number of a data unit transmitted before thecontrol protocol data unit is transmitted from a transmitting side.Additionally, the processing time information may comprise a sequencenumber of a data unit transmitted after the control protocol data unitis transmitted from a transmitting side.

Preferably, the processing time information is positioned in any of afirst, a last, or a middle part of the control protocol data unit. Theprocessing time information may be positioned in a super field of thecontrol protocol data unit.

In another aspect of the present invention, the radio link controlmodule is operated in an acknowledged mode. Also, the control protocoldata unit is at least one of a status protocol data unit, a piggybackedstatus protocol data unit, a reset protocol data unit, and a resetacknowledgment protocol data unit.

In a further aspect of the invention, the transmitter further comprisesmeans for receiving an instruction from an upper layer indicating to theradio link control module whether to include the processing timeinformation in the control protocol data unit.

In another embodiment of the present invention, a method for receiving acontrol protocol data unit in a receiving side of a wirelesscommunication system comprises receiving the control protocol data unithaving processing time information associated with the control data unitin a radio link control module and processing the control protocol dataunit according to the processing time information, wherein theprocessing time information indicates when to process the controlprotocol data unit by the receiving side.

Preferably, the processing time information comprises a sequence numberassociated with a data unit transmitted sequentially with the controlprotocol data unit from a transmitting side to the receiving side. Thedata unit and the control protocol data unit are used for at least oneof downlink communication and uplink communication. The radio linkcontrol module processes the control protocol data unit after processinga data unit having the same sequence number included in the processingtime information of the control protocol data unit. Alternatively, theradio link control module processes the control protocol data unit afterprocessing a data unit having a sequence number that is one smaller thanthe sequence number included in the processing time information of thecontrol protocol data unit.

In one aspect of the present invention, the processing time informationcomprises a sequence number of a data unit transmitted before thecontrol protocol data unit is transmitted from a transmitting side. Theprocessing time information may also comprise a sequence number that issubsequent to a sequence number of a data unit transmitted before thecontrol protocol data unit is transmitted from a transmitting side.Additionally, the processing time information may comprise a sequencenumber of a data unit transmitted after the control protocol data unitis transmitted from a transmitting side.

Preferably, the processing time information is positioned in any of afirst, a last, or a middle part of the control protocol data unit. Theprocessing time information may be positioned in a super field of thecontrol protocol data unit.

In another aspect of the present invention, the radio link controlmodule is operated in an acknowledged mode. Also, the control protocoldata unit is at least one of a status protocol data unit, a piggybackedstatus protocol data unit, a reset protocol data unit, and a resetacknowledgment protocol data unit.

In a further aspect of the invention, the method further comprisesreceiving an instruction from an upper layer indicating to the radiolink control module whether to process the control protocol data unitimmediately or according to the processing time information.

In another embodiment of the present invention, a method fortransmitting a control protocol data unit from a transmitting side of awireless communication system comprises generating a data unit in aradio link control module using data blocks received from an upperlayer, generating the control protocol data unit having processing timeinformation associated with the control protocol data unit in the radiolink control module, wherein the processing time information indicatesto a radio link control module of a receiving side when to process thecontrol protocol data unit, and transmitting the control protocol dataunit and the data unit to the receiving side in at least one of adownlink direction and an uplink direction.

Preferably, the processing time information comprises a sequence numberassociated with a data unit transmitted sequentially with the controlprotocol data unit from a transmitting side to the receiving side.

In one aspect of the present invention, the processing time informationcomprises a sequence number of a data unit transmitted before thecontrol protocol data unit is transmitted from a transmitting side. Theprocessing time information may also comprise a sequence number that issubsequent to a sequence number of a data unit transmitted before thecontrol protocol data unit is transmitted from a transmitting side.Additionally, the processing time information may comprise a sequencenumber of a data unit transmitted after the control protocol data unitis transmitted from a transmitting side.

Preferably, the processing time information is positioned in any of afirst, a last, or a middle part of the control protocol data unit. Theprocessing time information may be positioned in a super field of thecontrol protocol data unit.

In another aspect of the present invention, the radio link controlmodule is operated in an acknowledged mode. Also, the control protocoldata unit is at least one of a status protocol data unit, a piggybackedstatus protocol data unit, a reset protocol data unit, and a resetacknowledgment protocol data unit.

In a further aspect of the invention, the method further comprisesreceiving an instruction from an upper layer indicating to the radiolink control module whether to include the processing time informationin the control protocol data unit.

It is to be understood that both the foregoing general description andthe following detailed description of the present invention areexemplary and explanatory and are intended to provide furtherexplanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention.

FIG. 1 illustrates a related art UMTS network structure.

FIG. 2 illustrates a radio protocol architecture used in an UMTS.

FIG. 3 illustrates a format of an AM RLC PDU.

FIG. 4 illustrates a format of a status PDU.

FIG. 5 illustrates a format of a piggybacked status PDU.

FIG. 6 illustrates a format of a reset PDU/reset ACK PDU.

FIG. 7 illustrates a format of a status PDU in accordance with a firstembodiment of the present invention.

FIG. 8 illustrates a format of a piggybacked status PDU in accordancewith the first embodiment of the present invention.

FIG. 9 illustrates a format of a reset PDU/reset ACK PDU in accordancewith the first embodiment of the present invention.

FIG. 10 illustrates a format of a status PDU in accordance with a secondembodiment of the present invention.

FIG. 11 illustrates a format of a piggybacked status PDU in accordancewith the second embodiment of the present invention.

FIG. 12 illustrates a format of a reset PDU/reset ACK PDU in accordancewith the second embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. The present invention can be implemented in a mobilecommunications system such as a UMTS developed by the 3GPP. However, itcan also be applied to other types of communication systems.

A problem occurs when a control PDU is delivered to a receiver earlierthan a previously generated RLC PDU because the receiver can not knowwhen the control PDU was generated and transmitted. Specifically, thereceiver cannot determine the particular RLC PDU after which the controlPDU was generated and transmitted. The problem occurs because atransmitter does not inform the receiver of the exact RLC PDU that comesbefore the control PDU.

To solve the problem, the present invention provides a method fortransmitting a control PDU along with processing time information. Theprocessing time information informs a receiver of when the receivershould process the control PDU. Preferably, an AM RLC of a transmittertransmits the control PDU having operation control information thereinby including the processing time information. An AM RLC of the receiverprocesses the control PDU by using the processing time information suchthat error-free communication is achieved even if RLC PDUs aretransmitted out of sequence. Here, it is provided that the receiver andtransmitter may be a mobile terminal and a network, respectively, orvice versa.

Preferably, the processing time information may indicate a sequencenumber of the AM RLC PDU transmitted immediately before the control PDUis transmitted. Alternatively, the processing time information mayindicate a sequence number subsequently next to the sequence number ofthe AM RLC PDU transmitted immediately before the control PDU istransmitted. The processing time information may also indicate asequence number of an AM RLC PDU transmitted immediately after thecontrol PDU is transmitted.

FIGS. 7 through 9 illustrate formats of a control PDU in accordance witha first embodiment of the present invention. The formats of the controlPDU shown in the first embodiment may be used when processing timeinformation is positioned in front of the control PDU. In thisembodiment, sequence numbers have been used as the processing timeinformation; however, other types of processing time information may beused as long as processing time information is indicated. Furthermore,the sequence numbers used for the first embodiment have the same size(length) as that of an existing AM RLC PDU. However, the sequence numberof the control PDU does not have to be the size (i.e., 12 bits) of thesequence number used for the AM RLC PDU in a data transmission.Preferably, a sequence number of the control PDU having a size less than12 bits may be used for improving transmission efficiency.

FIGS. 10 through 12 illustrate formats of a control PDU in accordancewith a second embodiment of the present invention. The formats of thecontrol PDU shown in the second embodiment may be used when processingtime information is positioned in the rear of the control PDU. The aboveembodiments are merely exemplary, such that the present invention mayinclude different formats of the control PDU having the processing timeinformation located anywhere in a middle part of the PDU as well asbeing in a first or last part of the PDU.

In addition, in the present invention, in case of a status PDU and apiggybacked status PDU, the processing time information is preferablynot included in a header part of the PDU. Rather, the processing timeinformation is informed to the receiver by being indicated as a new SUFI(Super Field).

The SUFI comprises three fields of a type, a length and a value.Preferably, a new value referring to the processing time information maybe indicated in the type field and the processing time information maybe indicated in the value field. As a result, the processing timeinformation may be flexibly positioned within the status PDU or thepiggybacked status PDU.

When the AM RLC of the receiver receives the control PDU, processing ofthe control PDU is performed by using the processing time informationcontained in the control PDU. Preferably, the AM RLC of the receiverdoes not process the control PDU as soon as it is received, but instead,uses the processing time information included in the control PDU toperform processing at the time indicated by the corresponding processingtime information.

For example, when the RLC PDU is a data PDU, the AM RLC of the receiversequentially processes a received RLC PDU according to the sequencenumbers included in the data PDU. When the received RLC PDU is a controlPDU, the AM RLC of the receiver processes the control PDU according tothe processing time information included in the control PDU.

After the AM RLC receives the control PDU, if the processing timeinformation included in the control PDU is a sequence number, thefollowing data processing method may be performed. Preferably, the AMRLC of the receiver initially handles the processing time information.Preferably, the RLC PDU corresponding to an indicated sequence number isprocessed first, and then the contents included in the control PDU areprocessed afterward. Alternatively, the RLC PDU corresponding to asequence number that is one smaller than the indicated sequence numberis processed first, and then the contents included in the control PDUare processed afterward.

In the above procedure, when the AM RLC of the receiver processes theprocessing time information, namely, when the RLC PDU corresponding tothe indicated sequence number is processed first and then the contentsincluded in the control PDU are processed afterward, the processing timeinformation corresponds to the sequence number of the RLC PDUtransmitted just before the control PDU.

Alternatively, when the AM RLC of the receiver handles the processingtime information, namely, when the RLC PDU corresponding to a sequencenumber that is one smaller than the indicated sequence number isprocessed first, and then the contents included in the control PDU areprocessed afterward, the processing time information corresponds to asequence number that is one greater than the sequence number of the RLCPDU transmitted just before the control PDU.

Furthermore, when the AM RLC of the receiver processes the processingtime information, namely, when the RLC PDU corresponding to a sequencenumber that is one smaller than the indicated sequence number, and thenthe contents included in the control PDU are processed afterward, theprocessing time information may correspond to the sequence number of theRLC PDU transmitted immediately after the control PDU.

However, in a system such as the HSDPA system, techniques are used suchthat an out of sequence delivery does not occur. Therefore, includingthe processing time information, such as the sequence number, in thecontrol PDU may cause overhead and thereby degrade transmissionefficiency. Accordingly, the present invention additionally provides amethod for processing AM RLC data according to instructions from anupper layer. Preferably, when the upper layer indicates that acorresponding AM RLC requires the use of processing time information,the AM RLC includes such processing time information when sending thecontrol PDU. Once receiving the control PDU, the AM RLC handles thecontrol PDU by using the processing time information included in thecontrol PDU.

On the other hand, when the upper layer indicates that the AM RLC neednot use the processing time information, the processing time informationis not included in the transmitted control PDU. When the control PDUarrives at the receiver, the AM RLC may immediately process the controlPDU by using the information included in the control PDU.

As described in the present invention, effective communication may beachieved when a control PDU and an RLC PDU are delivered out of sequenceby including processing time information in the control PDU, which isreferred to by an AM RLC.

Although the present invention is described in the context of mobilecommunication, the present invention may also be used in any wirelesscommunication systems using mobile devices, such as PDAs and laptopcomputers equipped with wireless communication capabilities. Moreover,the use of certain terms to describe the present invention should notlimit the scope of the present invention to a certain type of wirelesscommunication system. The present invention is also applicable to otherwireless communication systems using different air interfaces and/orphysical layers, for example, TDMA, CDMA, FDMA, WCDMA, etc.

The preferred embodiments may be implemented as a method, apparatus orarticle of manufacture using standard programming and/or engineeringtechniques to produce software, firmware, hardware, or any combinationthereof. The term “article of manufacture” as used herein refers to codeor logic implemented in hardware logic (e.g., an integrated circuitchip, Field Programmable Gate Array (FPGA), Application SpecificIntegrated Circuit (ASIC), etc.) or a computer readable medium (e.g.,magnetic storage medium (e.g., hard disk drives, floppy disks, tape,etc.), optical storage (CD-ROMs, optical disks, etc.), volatile andnon-volatile memory devices (e.g., EEPROMs, ROMs, PROMs, RAMs, DRAMs,SRAMs, firmware, programmable logic, etc.).

Code in the computer readable medium is accessed and executed by aprocessor. The code in which preferred embodiments are implemented mayfurther be accessible through a transmission media or from a file serverover a network. In such cases, the article of manufacture in which thecode is implemented may comprise a transmission media, such as a networktransmission line, wireless transmission media, signals propagatingthrough space, radio waves, infrared signals, etc. Of course, thoseskilled in the art will recognize that many modifications may be made tothis configuration without departing from the scope of the presentinvention, and that the article of manufacture may comprise anyinformation bearing medium known in the art.

As the present invention may be embodied in several forms withoutdeparting from the spirit or essential characteristics thereof, itshould also be understood that the above-described embodiments are notlimited by an of the details of the foregoing description, unlessotherwise specified, but rather should be construed broadly within itsspirit and scope as defined in the appended claims, and therefore allchanges and modifications that fall within the metes and bounds of theclaims, or equivalence of such metes and bounds are therefore intendedto be embraced by the appended claims.

1. A receiver for receiving a control protocol data unit in a receivingside of a wireless communication system, the receiver comprising: meansfor receiving the control protocol data unit having processing timeinformation associated with the control data unit in a radio linkcontrol module; and means for processing the control protocol data unitaccording to the processing time information, wherein the processingtime information indicates when to process the control protocol dataunit by the receiving side, wherein the processing time informationcomprises a sequence number associated with a data unit transmittedsequentially with the control protocol data unit from a transmittingside to the receiving side, wherein the radio link control moduleprocesses the control protocol data unit after processing a data unithaving the same sequence number included in the processing timeinformation of the control protocol data unit or the radio link controlmodule processes the control protocol data unit after processing a dataunit having a sequence number that is one smaller than the sequencenumber included in the processing time information of the controlprotocol data unit, wherein the radio link control module is operated inan acknowledged mode (AM) and an instruction is received from an upperlayer indicating to the radio link control module whether to include theprocessing time information in the control protocol data unit, whereinthe processing time information is positioned in a super field of thecontrol protocol data unit such that the processing time information isflexibly positioned within at least one of a status protocol data unit,a piggybacked status protocol data unit, a reset protocol data unit, anda reset acknowledgment protocol data unit, wherein information in theprocessing time information other than the sequence number is also usedto indicate when to process the control protocol data unit, wherein thesuper field of the control protocol data unit comprises a type field, alength field, and a value field, and wherein a new value referring tothe processing time information is indicated in the type field of thesuper field and the processing time information is indicated in thevalue field of the super field.
 2. The receiver of claim 1, wherein thedata unit and the control protocol data unit are used for at least oneof downlink communication and uplink communication.
 3. The receiver ofclaim 1, wherein the processing time information comprises a sequencenumber of a data unit transmitted before the control protocol data unitis transmitted from a transmitting side.
 4. The receiver of claim 1,wherein the processing time information comprises a sequence number thatis subsequent to a sequence number of a data unit transmitted before thecontrol protocol data unit is transmitted from a transmitting side. 5.The receiver of claim 1, wherein the processing time informationcomprises a sequence number of a data unit transmitted after the controlprotocol data unit is transmitted from a transmitting side.
 6. Thereceiver of claim 1, wherein the processing time information ispositioned in any of a first, a last, or a middle part of the controlprotocol data unit.
 7. The receiver of claim 1, wherein the controlprotocol data unit is at least one of: a status protocol data unit; apiggybacked status protocol data unit; a reset protocol data unit; and areset acknowledgment protocol data unit.
 8. A transmitter fortransmitting a control protocol data unit from a transmitting side of awireless communication system, the transmitter comprising: means forgenerating a data unit in a radio link control module using data blocksreceived from an upper layer; means for generating the control protocoldata unit having processing time information associated with the controlprotocol data unit in the radio link control module, wherein theprocessing time information indicates to a radio link control module ofa receiving side when to process the control protocol data unit; andmeans for transmitting the control protocol data unit and the data unitto the receiving side in at least one of a downlink direction and anuplink direction, wherein the processing time information comprises asequence number associated with a data unit transmitted sequentiallywith the control protocol data unit from the transmitting side to thereceiving side, wherein the radio link control module processes thecontrol protocol data unit after processing a data unit having the samesequence number included in the processing time information of thecontrol protocol data unit or the radio link control module processesthe control protocol data unit after processing a data unit having asequence number that is one smaller than the sequence number included inthe processing time information of the control protocol data unit,wherein the radio link control module is operated in an acknowledgedmode (AM) and an instruction is received from an upper layer indicatingto the radio link control module whether to include the processing timeinformation in the control protocol data unit, wherein the processingtime information is positioned in a super field of the control protocoldata unit such that the processing time information is flexiblypositioned within at least one of a status protocol data unit, apiggybacked status protocol data unit, a reset protocol data unit, and areset acknowledgment protocol data unit, wherein information in theprocessing time information other than the sequence number is also usedto indicate when to process the control protocol data unit, wherein thesuper field of the control protocol data unit comprises a type field, alength field, and a value field, and wherein a new value referring tothe processing time information is indicated in the type field of thesuper field and the processing time information is indicated in thevalue field of the super field.
 9. The transmitter of claim 8, whereinthe processing time information comprises a sequence number of a dataunit transmitted before the control protocol data unit is transmitted.10. The transmitter of claim 8, wherein the processing time informationcomprises a sequence number that is subsequent to a sequence number of adata unit transmitted before the control protocol data unit istransmitted.
 11. The transmitter of claim 8, wherein the processing timeinformation comprises a sequence number of a data unit transmitted afterthe control protocol data unit is transmitted.
 12. The transmitter ofclaim 8, wherein the processing time information is positioned in any ofa first, a last, or a middle part of the control protocol data unit. 13.The transmitter of claim 8, wherein the control protocol data unit is atleast one of: a status protocol data unit; a piggybacked status protocoldata unit; a reset protocol data unit; and a reset acknowledgmentprotocol data unit.
 14. A method for receiving a control protocol dataunit in a receiving side of a wireless communication system, the methodcomprising: receiving the control protocol data unit having processingtime information associated with the control data unit in a radio linkcontrol module; and processing the control protocol data unit accordingto the processing time information, wherein the processing timeinformation indicates when to process the control protocol data unit bythe receiving side, wherein the processing time information comprises asequence number associated with a data unit transmitted sequentiallywith the control protocol data unit from a transmitting side to thereceiving side, wherein the radio link control module process thecontrol protocol data unit after processing a data unit having the samesequence number included in the processing time information of thecontrol protocol data unit or the radio link control module processesthe control protocol data unit after processing a data unit having asequence number that is one smaller than the sequence number included inthe processing time information of the control protocol data unit,wherein the radio link control module is operated in an acknowledgedmode (AM) and an instruction is received from an upper layer indicatingto the radio link control module whether to include the processing timeinformation in the control protocol data unit, wherein the processingtime information is positioned in a super field of the control protocoldata unit such that the processing time information is flexiblypositioned within at least one of a status protocol data unit, apiggybacked status protocol data unit, a reset protocol data unit, and areset acknowledgment protocol data unit, wherein information in theprocessing time information other than the sequence number is also usedto indicate when to process the control protocol data unit, wherein thesuper field of the control protocol data unit comprises a type field, alength field, and a value field, and wherein a new value referring tothe processing time information is indicated in the type field of thesuper field and the processing time information is indicated in thevalue field of the super field.
 15. The method of claim 14, wherein thedata unit and the control protocol data unit are used for at least oneof downlink communication and uplink communication.
 16. The method ofclaim 14, wherein the processing time information comprises a sequencenumber of a data unit transmitted before the control protocol data unitis transmitted from a transmitting side.
 17. The method of claim 14,wherein the processing time information comprises a sequence number thatis subsequent to a sequence number of a data unit transmitted before thecontrol protocol data unit is transmitted from a transmitting side. 18.The method of claim 14, wherein the processing time informationcomprises a sequence number of a data unit transmitted after the controlprotocol data unit is transmitted from a transmitting side.
 19. Themethod of claim 14, wherein the processing time information ispositioned in any of a first, a last, or a middle part of the controlprotocol data unit.
 20. The method of claim 14, wherein the controlprotocol data unit is at least one of: a status protocol data unit; apiggybacked status protocol data unit; a reset protocol data unit; and areset acknowledgment protocol data unit.
 21. A method for transmitting acontrol protocol data unit from a transmitting side of a wirelesscommunication system, the method comprising: generating a data unit in aradio link control module using data blocks received from an upperlayer; generating the control protocol data unit having processing timeinformation associated with the control protocol data unit in the radiolink control module, wherein the processing time information indicatesto a radio link control module of a receiving side when to process thecontrol protocol data unit; and transmitting the control protocol dataunit and the data unit to the receiving side in at least one of adownlink direction and an uplink direction, wherein the processing timeinformation comprises a sequence number associated with a data unittransmitted sequentially with the control protocol data unit from thetransmitting side to the receiving side, wherein the radio link controlmodule process the control protocol data unit after processing a dataunit having the same sequence number included in the processing timeinformation of the control protocol data unit or the radio link controlmodule processes the control protocol data unit after processing a dataunit having a sequence number that is one smaller than the sequencenumber included in the processing time information of the controlprotocol data unit, wherein the radio link control module is operated inan acknowledged mode (AM) and an instruction is received from an upperlayer indicating to the radio link control module whether to include theprocessing time information in the control protocol data unit, whereinthe processing time information is positioned in a super field of thecontrol protocol data unit such that the processing time information isflexibly positioned within at least one of a status protocol data unit,a piggybacked status protocol data unit, a reset protocol data unit, anda reset acknowledgment protocol data unit, wherein information in theprocessing time information other than the sequence number is also usedto indicate when to process the control protocol data unit, wherein thesuper field of the control protocol data unit comprises a type field, alength field, and a value field, and wherein a new value referring tothe processing time information is indicated in the type field of thesuper field and the processing time information is indicated in thevalue field of the super field.
 22. The method of claim 21, wherein theprocessing time information comprises a sequence number of a data unittransmitted before the control protocol data unit is transmitted. 23.The method of claim 21, wherein the processing time informationcomprises a sequence number that is subsequent to a sequence number of adata unit transmitted before the control protocol data unit istransmitted.
 24. The method of claim 21, wherein the processing timeinformation comprises a sequence number of a data unit transmitted afterthe control protocol data unit is transmitted.
 25. The method of claim21, wherein the processing time information is positioned in any of afirst, a last, or a middle part of the control protocol data unit. 26.The method of claim 21, wherein the control protocol data unit is atleast one of: a status protocol data unit; a piggybacked status protocoldata unit; a reset protocol data unit; and a reset acknowledgmentprotocol data unit.